package com.szakul.pdf.repository;

/**
 * Copyright (c) 2003-2006, www.pdfbox.org
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of pdfbox; nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * http://www.pdfbox.org
 *
 */

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.Calendar;

import java.net.URL;
import java.net.URLConnection;

import java.util.Date;

import org.apache.lucene.document.DateTools;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;

import org.apache.pdfbox.exceptions.CryptographyException;
import org.apache.pdfbox.exceptions.InvalidPasswordException;

import org.apache.pdfbox.util.PDFTextStripper;

/**
 * This class is used to create a document for the lucene search engine.
 * This should easily plug into the IndexHTML or IndexFiles that comes with
 * the lucene project.  This class will populate the following fields.
 * <table>
 *      <tr>
 *          <th>Lucene Field Name</th>
 *          <th>Description</th>
 *      </tr>
 *      <tr>
 *          <td>path</td>
 *          <td>File system path if loaded from a file</td>
 *      </tr>
 *      <tr>
 *          <td>url</td>
 *          <td>URL to PDF document</td>
 *      </tr>
 *      <tr>
 *          <td>contents</td>
 *          <td>Entire contents of PDF document, indexed but not stored</td>
 *      </tr>
 *      <tr>
 *          <td>summary</td>
 *          <td>First 500 characters of content</td>
 *      </tr>
 *      <tr>
 *          <td>modified</td>
 *          <td>The modified date/time according to the url or path</td>
 *      </tr>
 *      <tr>
 *          <td>uid</td>
 *          <td>A unique identifier for the Lucene document.</td>
 *      </tr>
 *      <tr>
 *          <td>CreationDate</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>Creator</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>Keywords</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>ModificationDate</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>Producer</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>Subject</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 *      <tr>
 *          <td>Trapped</td>
 *          <td>From PDF meta-data if available</td>
 *      </tr>
 * </table>
 *
 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
 * @version $Revision: 1.22 $
 */
public final class LucenePDFDocument {
    private static final char FILE_SEPARATOR = System.getProperty(
            "file.separator").charAt(0);

    // given caveat of increased search times when using
    //MICROSECOND, only use SECOND by default
    private DateTools.Resolution dateTimeResolution = DateTools.Resolution.SECOND;

    private PDFTextStripper stripper = null;

    /**
     * Constructor.
     */
    public LucenePDFDocument() {
    }

    /**
     * Set the text stripper that will be used during extraction.
     * 
     * @param aStripper The new pdf text stripper.
     */
    public void setTextStripper(PDFTextStripper aStripper) {
        stripper = aStripper;
    }

    /**
     * Get the Lucene data time resolution.
     * 
     * @return current date/time resolution
     */
    public DateTools.Resolution getDateTimeResolution() {
        return dateTimeResolution;
    }

    /**
     * Set the Lucene data time resolution.
     * 
     * @param resolution set new date/time resolution
     */
    public void setDateTimeResolution(DateTools.Resolution resolution) {
        dateTimeResolution = resolution;
    }

    //
    // compatibility methods for lucene-1.9+
    //
    private String timeToString(long time) {
        return DateTools.timeToString(time, dateTimeResolution);
    }

    private void addKeywordField(Document document, String name,
            String value) {
        if (value != null) {
            document.add(new Field(name, value, Field.Store.YES,
                    Field.Index.ANALYZED));
        }
    }

    private void addTextField(Document document, String name,
            Reader value) {
        if (value != null) {
            document.add(new Field(name, value));
        }
    }

    private void addTextField(Document document, String name,
            String value) {
        if (value != null) {
            document.add(new Field(name, value, Field.Store.YES,
                    Field.Index.ANALYZED));
        }
    }

    private void addTextField(Document document, String name, Date value) {
        if (value != null) {
            addTextField(document, name, DateTools.dateToString(value,
                    dateTimeResolution));
        }
    }

    private void addTextField(Document document, String name,
            Calendar value) {
        if (value != null) {
            addTextField(document, name, value.getTime());
        }
    }

    private static void addUnindexedField(Document document,
            String name, String value) {
        if (value != null) {
            document.add(new Field(name, value, Field.Store.YES,
                    Field.Index.NO));
        }
    }

    private void addUnstoredKeywordField(Document document,
            String name, String value) {
        if (value != null) {
            document.add(new Field(name, value, Field.Store.NO,
                    Field.Index.NOT_ANALYZED));
        }
    }

    /**
     * Convert the PDF stream to a lucene document.
     * 
     * @param is The input stream.
     * @return The input stream converted to a lucene document.
     * @throws IOException If there is an error converting the PDF.
     */
    public Document convertDocument(InputStream is) throws IOException {
        Document document = new Document();
        addContent(document, is, "<inputstream>");
        return document;

    }

    /**
     * This will take a reference to a PDF document and create a lucene document.
     * 
     * @param file A reference to a PDF document.
     * @return The converted lucene document.
     * 
     * @throws IOException If there is an exception while converting the document.
     */
    public Document convertDocument(File file) throws IOException {
        Document document = new Document();

        // Add the url as a field named "url".  Use an UnIndexed field, so
        // that the url is just stored with the document, but is not searchable.
        addUnindexedField(document, "name", file.getAbsolutePath());


        // Add the last modified date of the file a field named "modified".  Use a
        // Keyword field, so that it's searchable, but so that no attempt is made
        // to tokenize the field into words.
        addKeywordField(document, "modified", timeToString(file
                .lastModified()));

        String uid = file.getPath().replace(FILE_SEPARATOR, '\u0000')
                + "\u0000" + timeToString(file.lastModified());

        // Add the uid as a field, so that index can be incrementally maintained.
        // This field is not stored with document, it is indexed, but it is not
        // tokenized prior to indexing.
        addUnstoredKeywordField(document, "uid", uid);

        FileInputStream input = null;
        try {
            input = new FileInputStream(file);
            addContent(document, input, file.getPath());
        } finally {
            if (input != null) {
                input.close();
            }
        }

        // return the document

        return document;
    }

    /**
     * Convert the document from a PDF to a lucene document.
     * 
     * @param url A url to a PDF document.
     * @return The PDF converted to a lucene document.
     * @throws IOException If there is an error while converting the document.
     */
    public Document convertDocument(URL url) throws IOException {
        Document document = new Document();
        URLConnection connection = url.openConnection();
        connection.connect();
        // Add the url as a field named "url".  Use an UnIndexed field, so
        // that the url is just stored with the document, but is not searchable.
        addUnindexedField(document, "url", url.toExternalForm());

        // Add the last modified date of the file a field named "modified".  Use a
        // Keyword field, so that it's searchable, but so that no attempt is made
        // to tokenize the field into words.
        addKeywordField(document, "modified", timeToString(connection
                .getLastModified()));

        String uid = url.toExternalForm().replace(FILE_SEPARATOR,
                '\u0000')
                + "\u0000" + timeToString(connection.getLastModified());

        // Add the uid as a field, so that index can be incrementally maintained.
        // This field is not stored with document, it is indexed, but it is not
        // tokenized prior to indexing.
        addUnstoredKeywordField(document, "uid", uid);

        InputStream input = null;
        try {
            input = connection.getInputStream();
            addContent(document, input, url.toExternalForm());
        } finally {
            if (input != null) {
                input.close();
            }
        }

        // return the document
        return document;
    }

    /**
     * This will get a lucene document from a PDF file.
     *
     * @param is The stream to read the PDF from.
     *
     * @return The lucene document.
     *
     * @throws IOException If there is an error parsing or indexing the document.
     */
    public static Document getDocument(InputStream is)
            throws IOException {
        LucenePDFDocument converter = new LucenePDFDocument();
        return converter.convertDocument(is);
    }

    /**
     * This will get a lucene document from a PDF file.
     *
     * @param file The file to get the document for.
     *
     * @return The lucene document.
     *
     * @throws IOException If there is an error parsing or indexing the document.
     */
    public static Document getDocument(File file) throws IOException {
        LucenePDFDocument converter = new LucenePDFDocument();
        return converter.convertDocument(file);
    }

    /**
     * This will get a lucene document from a PDF file.
     *
     * @param url The file to get the document for.
     *
     * @return The lucene document.
     *
     * @throws IOException If there is an error parsing or indexing the document.
     */
    public static Document getDocument(URL url) throws IOException {
        LucenePDFDocument converter = new LucenePDFDocument();
        return converter.convertDocument(url);
    }

    /**
     * This will add the contents to the lucene document.
     *
     * @param document The document to add the contents to.
     * @param is The stream to get the contents from.
     * @param documentLocation The location of the document, used just for debug messages.
     *
     * @throws IOException If there is an error parsing the document.
     */
    private void addContent(Document document, InputStream is,
            String documentLocation) throws IOException {
        PDDocument pdfDocument = null;
        try {
            pdfDocument = PDDocument.load(is);

            if (pdfDocument.isEncrypted()) {
                //Just try using the default password and move on
                pdfDocument.decrypt("");
            }

            //create a writer where to append the text content.
            StringWriter writer = new StringWriter();
            if (stripper == null) {
                stripper = new PDFTextStripper();
            } else {
                stripper.resetEngine();
            }
            stripper.writeText(pdfDocument, writer);

            // Note: the buffer to string operation is costless;
            // the char array value of the writer buffer and the content string
            // is shared as long as the buffer content is not modified, which will
            // not occur here.
            String contents = writer.getBuffer().toString();

            StringReader reader = new StringReader(contents);

            // Add the tag-stripped contents as a Reader-valued Text field so it will
            // get tokenized and indexed.
            
            //System.out.println(contents);
            
            addTextField(document, "contents", reader);

            PDDocumentInformation info = pdfDocument
                    .getDocumentInformation();
            if (info != null) {
                addTextField(document, "Author", info.getAuthor());
                addTextField(document, "CreationDate", info
                        .getCreationDate());
                addTextField(document, "Creator", info.getCreator());
                addTextField(document, "Keywords", info.getKeywords());
                addTextField(document, "ModificationDate", info
                        .getModificationDate());
                addTextField(document, "Producer", info.getProducer());
                addTextField(document, "Subject", info.getSubject());
                addTextField(document, "Title", info.getTitle());
                addTextField(document, "Trapped", info.getTrapped());
            }
            int summarySize = Math.min(contents.length(), 500);
            String summary = contents.substring(0, summarySize);
            // Add the summary as an UnIndexed field, so that it is stored and returned
            // with hit documents for display.
            addUnindexedField(document, "summary", summary);
        } catch (CryptographyException e) {
            throw new IOException("Error decrypting document("
                    + documentLocation + "): " + e);
        } catch (InvalidPasswordException e) {
            //they didn't suppply a password and the default of "" was wrong.
            throw new IOException("Error: The document("
                    + documentLocation
                    + ") is encrypted and will not be indexed.");
        } finally {
            if (pdfDocument != null) {
                pdfDocument.close();
            }
        }
    }


}
